Behavior of two-way slabs subjected to drop-weight

Abstract

Prediction of punching shear strength in RC two-way slabs with different fiber volume fractions, and freely drop weight heights (Impact load) is fundamental to propose structural design procedures for structures subjected to impact load. Moreover, the punching failure of two-way slabs subjected to impact can consider as a complex behavior in design. Thus, the punching shear capacity of reinforced concrete (RC) two-way slabs subjected to drop-weight impacts investigated in this paper by using Nonlinear Finite Element Analysis (NLFEA). Firstly, the simulated models were validated against fifteen RC slabs with Polypropylene Fiber (PF) volume (Vf) of 0, 0.3, 0.6, and 0.9 % and subjected to impact load at the height of 0, 1.2, and 2.4 m. Then, the simulated slabs were expanded to cover slabs not subjected to impact load (impact height (HI) of 0 m) and slabs with Vf of 0 % to 1.2 % and subjected to impact load at the height of 1 m to 11m, resulting in a total of 182 RC slabs. The behavior of each slab evaluated in terms of the crack patterns, ultimate punching shear capacity, and deflection profile. The results showed that adding the PF at a dosage of 0.1 to 1.2 % by volume of concrete leads to significant enhancement in the overall structural behavior of the slabs and their resistance to impact loading. Attractively, after impact height of 10 m (KE = 686.00 J), the simulated RC slabs with PF volume fraction less than 0.7 % are failed. While all the simulated RC slabs subjected to impact load at the height of 11 m (KE 754.26 J) failed. Finally, NLFEA was also performed to provide a prediction for impact factor based on PF volume fraction and the impact load height.

Keywords

• engineering
• materials science
• technology
• civil engineering
• structural concrete